Signaling system for railroads



pril 2H, 1936. s. N. WIGHT l S'IGNALING SYSTEM FOR RAILROADSV Filed Aug.3o, l1929 VATTORNEY Patented Apr. 21, 1936 Nrrso STATES SIGNALING SYSTEMFOR RAILROADS Sedgwick N. Wight, Rochester, N. Y., assignor to1(rcrxizeral Railway SignalV Company, Rochester,

Application August 30, 1929, Serial No.- 389,446

17 Claims.

This invention relates to devices and systems for protecting trainmovements over power operated switches, and more particularly to meansfor locking such switches under predetermined conditions of trafiic, andis an improvement over the systems shown in my prior applications Ser.No. 48,553 led August 6, 1925 and Ser. No. 120,423 filed July 3, 1926.

Where track switches, operated by power under lo the control of anoperator, are employed, it is important that suitable pro-vision be madeto prevent the operator from carelessly or accidentally causingoperation of the switch by power in front of an approaching train, atsuch times and under such conditions that otherwise the switch might bein mid-stroke or unlocked when the train starts to pass over it. If thetrack is provided with track circuits for a sufcient distance from theswitch, such desired protection may be obtained by the application ofsome one of the well known schemes of track circuit controlled approachlocking; but in some cases, as on a passing siding or branch track, orthe like, such track circuits may not be available to indicate theypresence of a train approaching the switch, so that the ordinary typesof track circuit controlled: approach locking are not adequate toprotect the movement of a train from such a siding or branch track.

With these considerations in mind, in accordance with the presentinvention, it is proposed to employ a time element device, incombination with suitable control circuits and a stick relay or itsequivalent, in such a way that, whenever the signal is cleared toadvance trafc from the siding, branch track, or other portion of trackadjacent the switch and not equipped with track circuits, the switch cannot thereafter be operated by power, even though this signal isafterwards 40 caused to indicate stop, until after the lapse ofpredetermined time after a signal has been put to stop, sufficient topermit an approaching train either to come to a stop at the signal, orreach the point where the presence of the train prevents operation ofthe switch, dueI to the usual detectcr track circuit, or the like.

The characteristic features and advantages of the invention Will be inpart apparent to those skilled in the art, and in part pointed out, asthel description progresses.

The accompanying drawing shows in al simplifled and diagrammatic mannerone specic embodiment of the invention, applied to an electri-y callyoperated switch at the end of a passing sidv ing, the various parts andcircuits involved in the invention being shown more with the object offacilitating explanation and understanding of the nature of theinvention, than with the purpose of illustrating in detail the structureand arrangement of parts and circuits preferably employed in practice.

Referring to the accompanying drawing, one end of a passing siding PShas been shown, with a track switch SW. The main track, and the portionof the siding up to the fouling point are provided with insulated jointsand cross bonding, in accordance with common practice, to form adetector track circuit DTC, having a track relay T. The points of theswitch SW are locked and operated by a suitable power switch machine SM,which is assumed to beof the well known electrically operated type, suchasY disclosed, for example, in the patent to W. K. Howe, No.- 1,466,903,dated September 4, 1923. It is assumed that the operation of this switchmachine SM to its normal and reverse positionsfrom a local source ofcurrent, as a. battery 5, is controlled by an operator at',` a distantpoint, by means of a suitable remote controlA relay, such as a neutralpolar relay Z, which may be energized with `current of one or the otherpolarity, or de-energized, over line wires 6 and v'1, from a distantbattery 8, in accordance with the position of a manually operablepolechanging switch 9. 'I'he switch machine SM, however, may be operatedor controlled in any other suitable way, without departing from theinvention.

In the specific embodiment of the invention shown, the operation of theswitch machine SM is prevented, as and when desired, by directlycontrolling the supply of current from the bat'- tery 5 to the switchmachine motor, although other `expedienta'well known in the art, may beemployed for this same purpose. As shown, the connection from thebattery 5 to the switch machine SM includes the front contact Illof thedetector track relay T, and the front contact Il of a lock relay LR, sothat no power can be supplied to the switch machine, irrespective of theposition of the control relay Z, if the detector track circuit DTC isoccupied, or if the lock relay LR is de-energized.

Signals I 2 and l3fgovern traic toward the siding; signal I4 governstraffic on the main track; and signal l5, assumed to be a dwarf signal,governs traffic from the siding, all in accordance with common practice.These signals |2|5 have been illustrated as semaphore signals, buttrackway signals of any suitable type may be employed, such as colorlight signals. In accordance with this invention, these signals I2 to I5are provided with suitable circuit controllers I6, I'I, I8 and I9,respectively, which are closed only if the corresponding signal is inits stop position. If color light signals are employed, suitablecontacts on their control relays, or equivalent means, would be employedinstead of such circuit controllers. The dwarf signal I5 is alsoprovided with a circuit controller 25, closed when this signal indicatesstop.

These several signals I2-I5 are governed in accordance with the positionof the switch SW, the presence or absence of trains in advance of therespective signals, and under the control of the operator, in somesuitable way in accordance with common practice. For example, thesesignals may be controlled by separate levers, or may be remotelycontrolled, in accordance with the principles of the dispatching systemdisclosed, for example, in my prior application, Ser. No. 48,553, iiledAugust 6, 1925. Any suitable method of control of these signals,including the block signal circuits, may be employed in accordance withthe invention.

The invention contemplates a suitable time element device TE, and astick relay S, or equivalent means. This time element device TE may beof any suitable construction, operable electrically to close contactsafter the lapse of a predetermined time, such as 20 seconds. As showndiagrammatically, this time element device is of the thermal elementtype, such as disclosed more in detail in my prior application Ser. No.292,884, dated July 14, 1928, now matured into Patent No. 1,856,045,granted April 26, 1922, and comprises two thermal bi-metallic contactiingers 2I and 22, normally open, and adapted to be closed, after thelapse of a predetermined time, following the supply of heating currentto a coil 23 on the nger 22.

For simplicity in illustration, the control circuits for the relays LRand S, and the thermal time element device TE, have been shownconventionally with the symbols (-1-) and indicating the oppositeterminals of a suitable battery, or other source of current.

Operation-The stick relay S is normally energized, assuming that thedwarf signal I5 has not been cleared since the last movement of a trainover the switch, by a circuit which may be traced as follows: startingat (-1-), circuit controller 20 of signal I5, wires 25 and 26, coil 23of time element device TE, wire 21, front contact 28 of relay S, wires29 and 30, relay S, to On account of the resistance ofthe relay S inthis circuit, the

current in the coil 23 is not sufficient to heat the thermal nger 22.

With the stick relay S energized, and all of the signals l2-I 5 in thestop position, and assuming no train approaching the switch from eitherdirection on the main track, the lock relay LR is energized by a circuitwhich may be traced as followsz-starting at (-1-), front contact 3l ofrelay S, wire 32, circuit controller I8 of signal I4, wire 33, circuitcontroller I9 of signal I5, wire 34, circuit controller I6 of signal I2,wire 35, circuit controller I'I of signal I3, wire 36, contact a, wire31, relay LR, to The contact a in this circuit and its controlling relayb represent diagrammatically such contact or contacts as are necessaryto provide approach locking protection for the switch SW for trainsapproaching on the main track in either direction. Such approach lockingcircuits, although some suitable form is preferably employed in thepractical application of the invention, are not material to theinvention, and may be of any suitable type, such as disclosed, forexample, in my prior application, Ser. No. 48,553, led August 6, 1925.

Under the conditions assumed, that is, with the signals I2-I 5 allindicating stop, and no train approaching from either direction on themain track, and with the lock relay LR energized, the switch machine SMmay be supplied with current to operate the switch points to eitherposition, dependent upon the position of the manually operable switch 9and energization of the remote control relay Z.

Considering now the train movement, to which this invention moreparticularly relates, assume that the operator, having caused the switchSW to assume the reverse position, and having cleared the dwarf signalI5, with the idea of permitting a train to move from the passing sidingPS onto the main track, should for some reason change his mind, andcause the signal I5 to assume the stop position; or, perhaps, themanipulation clearing the signal I5 was made accidentally orthoughtlessly, and is then changed. Under these conditions, if thereshould happen to be a Vtrain on the passing siding PS approaching thesignal I5, and if the engineman observing this signal in the clearposition, should maintain `or increase speed, this train might not beable to stop, when the signal I5 was placed in the stop position; andunless some special provisions were made to prevent operation of theswitch machine, other than merely the fact that the signal I5 is in thestop position, the switch machine might be operating at the time thetrain in question entered the detector track circuit DTC, with theresult that the train might reach the Switch points when unlocked or inmid-stroke. This would be true if the entrance of the train into thedetector track circuit DTC should at once cut off the power foroperating the switch machine, as in the arrangement shown, or ifprovisions were made, as shown, for example, in the patent to W. K. HoweNo. 1,399,257, dated December 6, 1921, to permit the switch machine tocomplete the cycle of operation that had been started. Although such atrain movement would trail through the switch points, and might notderail the train,

the possible injury to the switch points or switch operating mechanismmakes it desirable to avoid such a contingency. Also, under theconditions assumed, the switch machine may be operated to its normalposition, and under certain circumstances the signals I2 or I4 cleared,with the possibility that conflicting train movements on the main trackmight occur under conditions that might be unsafe with a train comingoil" of the siding.

This invention prevents operation of the switch under the conditionsassumed. When the dwarf signal I5 is cleared, its circuit controller 28opens and de-energizes the stick relay S, thereby breaking at its irontcontact 3| the energizing circuit for the lock relay LR, so as toprevent application of power to the swit-ch machine SM. When the signalI5 is caused to assume its stop position by the operator, as in the caseassumed, the stick relay S and the lock relay LR remain de-energized;Vand the switch machine SM cannot again be operated until the relay S isagain picked up.

When the signal I5 is put back in its stop position, closing its circuitcontroller 2D, the coil 23 of the time element device TE is suppliedwith current through a circuit from circuit controller 2l), wires 25 and26, coil 23, wire 21 and back contact 28 of relay S, to This circuit forthe coil 23 does not include the relay S; and this current in the coil23 is sucient to heat the thermal element constituting the nger 22 andcause this linger to contact with the other linger 2I, after a timeinterval, thereby establishing a pick-up circuit for the relay S fromcircuit controller 20, wires 25 and 26, fingers 22-2I, wires38, 39, and3D, relay S to When the relay S is thus re-energized, it breaks at itsback contact 28 the heating circuit for the coil 23, which then cools,opening the contacts 2I-22, ready for the next operation.

The time element device TE is so designed and adjusted that, before thecontact iingers 2|-22 engage each other, a predetermined time, such as20 seconds must elapse. This time interval is selected such that a traino-n the passing siding PS, approaching the signal I5, will either havetime to stop, after the signal I5 has been put in the stop position, orif unable to stop, will run by the signal l5 into the detector trackcircuit DTC. When the train reaches the detector track circuit, thedropping of the track relay T prevents the operation of the switchmachine SM, independently of the control of the relay LR, so that, ifthe approaching train is unable to stop and runs by the signal I5, theswitch can not be operated by power until the train has advanced orbacked up clear of this detector track circuit. It will be evident thatthis time interval should take into consideration the speed of trains onthe passing siding PS, the sighting distance of the signal I5, and thebraking distance of such trains; and any desired time interval may beemployed, as found best adapted to particular operating conditions.

In the case of a normal movement of a train from the passing siding PS,the stick relay S is at once re-energized, without the time intervaldelay, because the signal I5 automatically assumes the stop position,upon movement of the train thereby, due to the usual track circuitcontrol of this Vsignal (not shown), and with the track relay Tde-energized, a pick-up circuit for the stick relay S is establishedfrom (-1-), circuit controller 20, wires 25 and 40, back contact il ofthe track relay T, wires 39 and 30, relay S to Thus, in the case of anormal train movement off of a siding, as soon as the train has clearedthe detector track circuit DTC, the switch may be operated, withoutwaiting for the time element device TE to close its contacts 2 I-22.This no-t only saves unnecessary delay in many instances, but alsoavoids the unnecessary operation of the time element device TE.

From the foregoing, `it can be seen that there is provided by thisinvention a simple and efcient means for affording the necessaryapproach locking control of a switch for train movements from passingsidings, branch tracks, or similar stretches of track, which are notequipped with track circuits. It will be evident that the principles andessential features of the invention may be applied to varying conditionsencountered in practice, and it should be understood that the .inventionis not limited to the particular construction and arrangement of partsshown and described.

What I claim is:-

1. In a system of the type described, the combination with a poweroperated track switch and a signal governing traflic over the switch, ofa stick relaycontrolling the application of power to the switch, a stickcircuit for said relay broken when said signal indicates clear, apick-up circuit for said relay, a thermally actuated time responsivedevice which when in its active condition closes said pick-up circuit,and an energizing circuit for rendering said time responsivel deviceactive closed only if said stick relay is deenergized and said signalindicates stop.

2. A system of the character described comprising, in combination with apower operated track switch and a signal governing traffic over theswitch, of a relay acting while `de-energized to prevent operation ofthe switch, and an energizing circuit for said relay including thecontacts of a thermal element time responsive device, said thermalelement of said device being heated when said relay is deenergized andsaid signal indicates stop.

3. A system for protecting a train moving over power operated switchescomprising, a stick relay governing the operation of the switch, athermal time-responsive device for governing said relay and eiectiveonly if said siding signal is at stop, a main track signal associatedwith said switch, a siding signal associated with said switch, adetector track relay for controlling the energization of said stickrelay independently of said thermal device, a lock relay which ifdeenergized prevents the-operation of said switch, and a circuit forsaid lock relay including a front contact of said stick relay and acontact closed only if said main signal is at stop.

4. In combination, a track switch, a signal for governing traflic oversaid track switch, a lock relay which if deenergized prevents operationof said track switch, a stick relay having a front Contact in theenergizing circuit of said lock relay, a thermal relay, a pick-upcircuit for said stick relay including a front contact of said thermalrelay, and a circuit for the heating coil of said thermal relayincluding a contact closed when said signal is at stop.

5. In combination, a track switch, a signal for governing trac over saidtrack switch, a lock relay which if deenergized prevents operation ofsaid track switch, a stick relay having a front contact in theenergizing circuit of said lock relay, a thermal relay, a pick-upcircuit for said stick relay including a front contact of said thermalrelay; and a circuit for the heating coil of said thermal relayincluding a contact closed when said signal is at stop and including aback contact of said stick relay.

Y 6. In combination, a track switch, a signal for governing trailic oversaid track switch, a lock relay which if deenergized prevents operationof said track switch, a stick relay having a front contact in theenergizing circuit of said lock relay, a thermal relay, a pick-upcircuit for said stick relay including a front contact of said thermalrelay, a circuitl for the heating coil of said thermal relay including acontact closed when said signal is at stop, and a contact open whenthere is a train approaching said switch included in `the energizingcircuit of said lock relay.

said signal is at stop and including a back contact of said stick relay,and a contact open when there is a train approaching said switchincluded in the energizing circuit of said lock relay.

8. In combination, a stick relay for at times preventing the movement ofswitch points of a railway track switch, a thermal relay having anormally open contact, an energizing circuit for said thermal relayincluding a contact closed only when a signal associated with said trackswitch is at stop and a contact closed when said stick relay assumes itsdeenergized condition, and a pick-up circuit for said stick relayincluding said contact of said thermal relay.

9. In combination, a stick lock relay for at times preventing themovement of switch points of a railway track switch, a thermal relayhaving a normally open contact, an energizing circuit for said thermalrelay including ra contact closed only when a signal associated withsaid track switch is at stop, a pick-up circuit for said lock relayincluding said contact o f said thermal relay, and

a stick circuit for said lock relay closed only if said signal is atstop.

10. In combination, a lock stick relay for at times preventing themovement of switch points of a railway track switch, a thermal relayhaving a normally open contact, an energizing circuit for said thermalrelay including a contact closed only when a signal associated with saidtrack switch is at stop, a pick-up circuit for said stick lock relaycontrolled by a contact of said thermal relay, and a stick circuit forsaid lock relay including a contact open when said signal is cleared.

1l. In combination, a track switch of a railway system, a power operatedswitch machine for operating said track switch, a signal for governingmovement of trailic over said track switch, a stick relay for at timespreventing operation of said switch machine and having a stick circuitclosed only if said signal is at stop, a thermal relay having a contactopen when in its deenergized cool condition, an energizing circuit forsaid thermal relay including a contact closed only when said signal isat stop, and a pick-up circuit for saidstick relay including saidcontact of said thermal relay. Y

12. In combination, a track switch of a railway system, a power operatedswitch machine for operating said track switch, a signal for governingmovement of traic over said track switch, a lock stick relay for attimes preventing operation of said switch machine and having a stickcircuit closed only if said signal is at stop, a thermal relay having acontact open when in its deenergized cool condition, an energizingcircuit for said thermal relay including a contact closed only when saidsignal is at stop, and a pick-up circuit for said lock relay includingsaid contact of said thermal relay.

l3.`In combination, a track switch of a railway system, a power operatedswitch machine for operating said track switch, a signal for governingmovement of traffic over said track switch, a lock stick relay for attimes preventing operation of said switch machine, a thermal relayhaving a contact open when in its deenergized cool condition, anenergizing circuit for said thermal relay including a contact closedonly when said signal is at stop, a pick-up circuit for said lock relaycontrolled by a contact of said thermal relay, and a stick circuit forsaid stick relay controlled by said signal, a lock repeater relaycontrolled by said stick relay and when deenergized preventing operationof said track switch, said lock repeater relay including a contact openwhen there is a train approaching said track switch.

lll. In combination, a track switch, a signal for governing trac oversaid track switch, a lock relay which if deenergized prevents operationof said track switch, a stick relay having a front contact in theenergizing circuit of said lock relay, an approach relay having acontact opened when there is a train approaching ineluded in theenergizing circuit of said lock relay, a thermal relay, a pick-upcircuit for said stick relay including a front contact of said thermalrelay, and a circuit for the heating coil of said 'thermal relayincluding a contact closed when said signal is at stop.

15. In combination, a lock stick relay for at times preventing themovement of switch points of a railway track switch, a thermal relayhaving a normally open Contact, an energizing circuit for said thermalrelay including a contact closed only when a signal associated with saidtrack switch is at stop, a pick-up circuit i'or said lock relayincluding said contact of said thermal relay, a second pick-up circuitfor said stick relay including a back contact of a detector track relayassociated with said track switch, and a stick circuit for said lockrelay closed only if said signal is at stop.

16. In combination, a track switch capable of setting up a main and adiverging route, a main signal governing traffic over said main route, adiverging route signal for governing traffic over said diverging route,a lock relay for preventing operation of said track switch, a stickrelay, a circuit for said lock relay including a front contact of saidstick relay and a contact closed only if said main signal is at stop, a.pick-up circuit for said stick relay, thermal relay means for closingsaid pick-up circuit a predetermined time after said diverging routesignal has been put to stop, and a stick circuit for said stick relaybroken if said diverging route signal is cleared.

17. A system for protecting trains moving over power-operated trackswitches comprising, a stick relay which must be energized to permitpower operation of a track switch, a signal for governing the movementof traflic over said track switch, an electrically controlled thermalrelay the energizing circuit of which may be closed only if said stickrelay is deenergized and said signal is at stop and having a contactclosed only if said thermal relay has been energized for a predeterminedperiod of time, a pick-up circuit for said stick relay including saidcontact, a second pick-up circuit for said stick relay including a backcontact of a detector track relay associated with said track switch, anda stick circuit for said stick relay including a contact closed only ifsaid signal is at stop.

SEDGWICK N. WIGH'I.

